Flexible packages such as bags or pouches are relatively inexpensive and convenient for containing a variety of food items such as snacks, cold cuts, cookies, pasta, or other food items or non-food items, which are produced on a mass production continuous basis. Flexible packages serve to store the enclosed products, protect the enclosed goods from spoiling or contamination, keep the enclosed goods together and facilitate handling of the goods as a single unit, provide tamper resistance and tamper evidence. To achieve these purposes, flexible packages containing food items are sealed with various types of seals and delivered sealed to the end user of such items. To gain access to the enclosed goods, the flexible package has to be opened by breaking or tearing off the seal. In many cases, the packages contain a plurality of items, such as cookies, various snacks, pasta, or cold cuts that may not be consumed at once. For convenience, it is usually desirable to maintain the remaining items in the original package and remove the remaining items from the package later and, often, in several portions. It is, therefore, important to remove the permanent seal with minimal damage to the rest of the package while tearing off or breaking the permanent seal. Also, in cases when not all of the packaged product is consumed at once, it may be desirable for the package to be reclosable or resealable. This feature allows the consumer to re-open the package after it has been initially opened for easy and repeat access to the items stored in the package on the one hand. On the other hand, it allows the consumer to close or reseal the package for freshness, protection, and storage of unused items in the original package.
Sealed flexible packages that can be easily opened, and, if desired, resealed or reclosed, and methods and machines for making such flexible packages have been known and disclosed in the art.
U.S. Pat. No. 2,949,370 to Hughes discloses a bag with an outer permanent seal and inner reclosable seal. The reclosable seal can be in the form of an adhesive strip, which covers a slot and is engaged with itself to reseal the bag. No intermediate perforation for easy removal of the permanent seal is disclosed.
U.S. Pat. No. 3,330,469 to Koncak discloses a resealable bag comprising a permanent seal, a line along which the permanent seal can be cut off, and an inner reclosable strip. The reclosable strip is a metallic strip that is much stiffer than the bag and allows the bag to stay closed when the bag is folded along a line extending along the metallic strip.
U.S. Pat. No. 3,473,589 to Gotz discloses an interlocking reclosable seal and a permanent seal that is cut off along predetermined lines of weakened tear resistance. The design of the tear line is not provided.
U.S. Pat. No. 3,519,197 to Campbell discloses a permanently sealed bag that can be easily opened along a "line of weakness", i.e. a perforated line that appears on one side wall of the bag. There is no disclosure of any reclosable seals, or tear-off of the permanent seal.
U.S. Pat. No. 3,780,781 to Uramoto discloses a resealable bag with reclosable profiles, reinforced upper tear-off strips and tear lines of weakened resistance between the reclosable profiles and the reinforced tear-off strip.
U.S. Pat. No. 3,827,472 to Uramoto discloses a resealable bag with reclosable profiles and a tear strip which tears between pairs of guide ribs formed integrally with the inner layers of the bag above the reclosable profiles. The tear line, it is disclosed, does not deviate downwardly or turn upwardly. The guide ribs may be replaced by a perforated line of weakened resistance such as by spaced notches or a V-groove.
U.S. Pat. No. 3,850,780 to Crawford et al. discloses a wrapping machine that produces and heat seals bags made from flexible thermoplastic web material.
U.S. Pat. No. 3,943,686 to Crawford et al. discloses a wrapping machine wherein regularly spaced articles are entubed in a flexible wrapping material, and the tube is sealed and cut between the wrapped articles using rotary crimping heads.
U.S. Pat. No. 4,106,265 to Aterianus discloses a wrapping machine which forms a tube of wrapping material around spaced articles, and seals the articles inside the wrapping film. A rotary crimping, sealing and cut-off device is used to seal the tube and separate the wrapped articles from one another.
U.S. Pat. No. 4,285,105 to Kirkpatrick discloses a bag having reclosable interlocking profiles that change color upon occlusion or locking. The patent does not disclose perforated or any other tear-off lines, or a permanent seal.
U.S. Pat. No. 4,572,377 to Beckett discloses a reclosable, tamper evident package made from flexible polymeric material that has a tear strip on only one face of the package. An adhesive reclosable seal is parallel to the permanent closure and a tear strip is formed in-between the permanent closure and resealable seal. The tear strip can be made from a series of Z-shaped cuts or any other known form that allows the tear strip to be easily removed from one face of the package. When the tear strip is removed from one face of the bag, the permanent closure is still attached to the other face of the bag.
U.S. Pat. No. 4,712,357 to Crawford et al. discloses a computer controlled horizontal wrapping machine which wraps a film around spaced articles, and seals and severs the film between the articles using rotary crimping, sealing heads.
U.S. Pat. No. 4,786,190 to Van Erden et al. discloses different bag designs with permanent and reclosable seals. In one of the designs, the reclosable seal is attached to a flap extending across the width of the bag. The non-reclosable closure has a perforated line concealed by the flap. In another design, the reclosable seal is located above the permanent or non-reclosable seal. There is no disclosure of a tear off line of specific design for any of the embodiments.
U.S. Pat. No. 4,986,673 to Bell discloses a resealable bag comprising a permanent heat seal, a reclosable seal (profile engagement members) and a gap portion extending between the wide heat seal and the reclosable seal. The tear line extends across the gap portion upon tearing off of the heat seal. The patent also discloses tear notches to facilitate tearing. The reference teaches away from score lines. Undesirable cross tears are avoided by use of a reinforced tab portion or permanent seal.
U.S. Pat. No. 5,678,390 to Pruett et al. discloses a horizontal film packaging machine comprising rotary crimping and sealing assembly for sealing heads. The machine has improved temperature control of the sealing surfaces. No perforation knife is disclosed.
U.S. Pat. No. 5,725,311 to Ponsi et al. discloses a resealable bag or plastic package having a reclosable adhesive label which conceals an opening in the bag. The label is used to open and to re-close the opening.
U.S. Pat. No. 5,741,075 to Collins et al. discloses a resealable flexible bag having a label with two adhesive areas separated by a non-adhesive area which extends over an opening.
The present invention provides a flexible, easy to open package that is sealed with permanent seals to protect articles packaged within the package prior to utilization of the packaged articles. The package according to the present invention allows for quick and easy removal of one of the permanent seals, such as one across the top of the package. A perforated line, or a line of weakened tear resistance, is formed of a plurality of hook-like cuts extending across the bag below the permanent seal. The hook designs of the tear line provide not only a quick and easy removal of the permanent seal but also minimizes cross-tearing of the package towards the top edge or towards the bottom edge. The hook designs also provide a scalloped edge when the top seal is torn along the perforated line, thereby providing tamper evidence superior to conventional perforated lines formed of a plurality of straight in-line cuts. The hook designs of the present invention may be employed on all types of flexible packages such as flexible bags and pouches for food and non-food items.
In embodiments of the invention, the package is a reclosable package that can be reopened and reclosed several times. The reclosable feature may be in the form of interlocking profiles or a pressure sensitive adhesive seal that may also be tamper evident.
The invention further provides for a perforation or cutting knife comprising a perforation edge of a specific design that allows for manufacturing of the flexible bags having a line of weakened tear resistance which is formed of a plurality of hook-like cuts.